1. Field of the Invention
The invention and its various embodiments disclosed herein relate to a pump system for extracting well fluids from below the ground. More particularly, the invention relates to devices and methods for extracting well fluids and directing debris away from the barrel or casing of a well.
2. Description of Related Prior Art
Conventional pumping systems for extracting oil from the ground include an above-ground pumping unit and a down-hole pumping system. The down-hole pumping system typically includes a barrel and casing that lines the hole. Disposed inside the barrel are inserted a rod (“sucker rod”) that couple to standard American Petroleum Institute (“API”) plungers and plunger connectors. The action of a plunger driven by a sucker rod creates suction based on the system's up and down strokes. Suction is created by the plunger having an annular lumen with an internal valve at the bottom of a plunger that closes on upstroke and then opens on down stroke allowing well fluids to enter the bottom of a plunger and out through an opening at the top of a plunger and through one or more ports on the connector. Typical well pump systems can also include a barrel evacuating chamber between a lower valve on a plunger and a valve at the bottom of the pump system where fluids flow from the fluid deposit into the evacuation chamber and through the plunger depending on the pump stroke.
Problems with traditional plungers have been that along with well fluids being pumped through the pump system, this includes debris such as sand and other fines that get forced up and out of the plunger and which then settle between the plunger and the barrel causing the side of the plunger to become grooved, lose functionality and performance. If enough debris becomes lodged between the plunger and the barrel, the pump can lock into place. This has largely been caused by the slope of the top of the plunger which in a standard API plunger connector slopes downward from a central axis of the connector to the barrel wall wherein debris is pushed toward the side of the plunger and barrel when the debris settles.
The problem of debris clogging plungers has been previously addressed by Muth. (See, e.g., U.S. Pat. No. 6,250,392, FIG. 12) Muth attempted to overcome the above-described problem by disposing the plunger connector internal to the lumen of the plunger and creating an open-top plunger design. Additionally, Muth created a tapered edge which would direct debris into the interior of the plunger such that the plunger would act to trap debris which could then be expelled on the down stroke. Therefore, currently, those in the field are faced with the choice of using a Muth plunger or, using a standard API plunger and the problems that come with it.
A further attempt to prevent debris from becoming trapped between a barrel and plunger was described by Havard, U.S. Pat. No. 6,145,590, which attempted to prevent debris through the use of a flexible annular ring around a plunger connector.
What is needed is a device that can incorporate the benefits of preventing debris from becoming trapped between a plunger and the hole barrel yet also utilizes standard plunger technology. Further, what is also needed is a method for using hydraulic pressure through an extra valve internal to the connector to expel debris upwards and away from the plunger to production tubing.